Iodine‐Catalyzed Double [4+2] Oxidative Annulations for the Synthesis of Bipyrazines from Ketones and Diamines by a Domino Strategy

Abstract

An iodine-catalyzed double [4 + 2] oxidative annulation of ketones and diamines is described. A multi-pathway coupled domino strategy has been developed for the synthesis of substituted dimeric pyrazines under metal-free conditions. One CÀ C and four CÀ N bonds are formed during this double [4 + 2] oxidative annulation process from two ketones and two diamines.

Copper-Promoted Aerobic Oxidative [3+2] Cycloaddition Reactions of N,N-Disubstituted Hydrazines with Alkynoates: Access to Substituted Pyrazoles

“…Subsequently, deprotonation of intermediate 11 affords intermediate 12 , which is detected by GC–MS (see Figure S2). Finally, the desired product 3a is obtained from intermediate 12 through an aerial oxidation procedure using oxygen as the green oxidant …”

“…Finally, the desired product 3a is obtained from intermediate 12 through an aerial oxidation procedure using oxygen as the green oxidant. 40…”

Efficient synthesis of spiro diheterocycles via multi-component dicyclization reaction

“…Spiro-2,3-dihydrobenzofuran is a prominent structural skeleton, which ubiquitously exists in many medicinal and natural products. 1 Examples include griseofulvin, 2 furaquinocin A 3 and corallidictyal D. 4 Moreover, there are also several biologically active dihydrobenzofuran cores, including stachybotrylactam which is used as the HIV-1 protease inhibitor 5 and XEN907 which is used as the hNav1.7 blocker. 6 Thus, several methods have been developed for the synthesis of these skeletons, such as [4 + 1] cycloaddition reaction 5,7 and dearomatization of benzofurans.…”

Oxoammonium salt-promoted diverse functionalization of saturated cyclic amines with dinucleophiles

“…By contrast, using benzene-1,2-diamines as 1,4-dinucleophiles, cascade functionalization and C–N bond cleavage of cyclic amines selectively occurs to afford difunctionalized acyclic amines 3-(quinoxalin-2-yl)propan-1-amines based on β-oxo cyclic iminium ion intermediates (Scheme 1(B)). Bearing in mind the importance of both functionalized alicyclic amines 1 and 2-substituted quinoxalines, 12 we made a detailed study of this aspect.…”

“…and KSCN (1 equiv.) in DMF at rt under air for 6 h. Considering the importance of functionalized quinoxaline, 12 the suitability of different N -aryl piperidines 1 in this conversion was investigated. It showed that substrates 1 bearing an electron-donating group (Me) or an electron-withdrawing group (F, Cl or Br) attached at the ortho -, meta - or para -position of the aryl moiety were compatible for this reaction and afforded 5b–5k in moderate to good yields (50–74%).…”